1-Benzyl 3-(4-methoxyphenyl)methyl (3RS,4SR)-3-[2-(tert-butoxy)-2-oxoethyl]-4-methylpyrrolidine-1,3-dicarboxylate → 1-benzyl 3-(4-methoxyphenyl)methyl (3R*,4S*)-3-[2-(tert-butoxy)-2-oxoethyl]-4-methylpyrrolidine-1,3-dicarboxylate

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Reaction Steps

1-Benzyl 3-(4-methoxyphenyl)methyl (3RS,4SR)-3-[2-(tert-butoxy)-2-oxoethyl]-4-methylpyrrolidine-1,3-dicarboxylate obtained in Example 4c (12.7 g, 26 mmol) was optically resolved repeatedly by HPLC (CHIRALPAK AD-H (2 cm diameter×25 cm), elution solvent: hexane/ethanol=85/15, flow rate: 8-10 ml/min.) to give a chiral form corresponding to the peak with a shorter retention time (5.7 g, yield: 44.9%). The resulting chiral form (5.3 g) was further purified by silica gel column chromatography (elution solvent; heptane/ethyl acetate) in two portions to give 5.2 g of the title compound.

Provenance & Evidence